package com.itheima.reggie.controller;

import com.itheima.reggie.common.R;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.UUID;

@RestController
@RequestMapping("/common")
public class CommonController {
    @Value("${reggie.path}")
    private String path;

    //文件上传
    @PostMapping("/upload")
    public R<String> upload (MultipartFile file) throws IOException {
        //1. 获取文件的原始文件名, 通过原始文件名获取文件后缀
        String originalFilename = file.getOriginalFilename();  //获取文件名
        String suffixName = originalFilename.substring(originalFilename.lastIndexOf("."));  //获取后缀

        //2. 通过UUID重新声明文件名, 文件名称重复造成文件覆盖
        String uuidFileName = UUID.randomUUID().toString()+suffixName;

        //3. 创建文件存放目录
        File dir = new File(path);
        if (!dir.exists()){
            //如果不存在就创建
            dir.mkdir();
        }

        //4. 将上传的临时文件转存到指定位置
        File destFile = new File(dir,uuidFileName);
        file.transferTo(destFile); //把原始文件拷贝到目标位置
          //注意：返回的名字一定要是存储在服务器中的名字，前端需要根据名字去访问内容
        return R.success(uuidFileName);
    }

    //文件下载 (返回值类型是void)
    @GetMapping("/download")
    public void download(String name, HttpServletResponse response) throws IOException {
        //1.定义输入流，通过输入流读取文件内容
            //找到目标文件
        File destFile = new File(path,name);
        FileInputStream fileInputStream = new FileInputStream(destFile);

        //2.通过response对象，获取到输出流
        ServletOutputStream outputStream = response.getOutputStream();

        //3.通过response对象设置响应数据格式（image/jpeg）
        response.setContentType("image/jpg");

        //4.通过输入流读取文件数据，然后通过上述的输出流写回浏览器
        byte[] buf = new byte[1024];
        int length = 0;
        while ((length = fileInputStream.read(buf))!=-1){
            outputStream.write(buf,0,length);
        }

        //5.关闭资源
        outputStream.close();

    }
}
